Endotracheal tubes have been known for years and have been routinely employed to prevent upper airway obstruction or to facilitate artificial ventilation of unconscious or anesthetized patients. Such tubes are inserted through the mouth or nasal passage and extend into the trachea of the patient. These tubes generally include an external, resilient sleeve, conventionally referred to as a "cuff", which is inflatable with air following insertion of the device into the human mid-trachea portion. Inflation of the cuff effects an airtight seal of the space between the tube and the surrounding body tissue, i.e., the inner wall of the trachea. The tubular portion of these devices is comprised of a fairly rigid plastic material to prevent the artificial airway from collapsing when in the body.
When inserted into the patient's throat, an endotracheal tube assumes a generally curved, hook shaped configuration to conform to the passage connecting the mouth or nasal cavity with the trachea. In this position, the endotracheal tube necessarily traverses the delicate structures of the larynx, and the stressed, curved configuration of the tube forces it into direct pressure contact with the posterior region thereof. Importantly, this region of the larynx is particularly sensitive in that it is comprised of joints between cartilages and ligaments. Particularly delicate parts of the posterior region of larynx are the aryntenoid cartilages which rotate the ventricular ligaments (true vocal cords) and the posterior commissure which comprises the junction of the ventricular ligaments. In this respect, the aryntenoid cartilages and posterior commissure may be damaged by prolonged contact and pressure from the endotracheal tube. Still further, engagement of the tube with the posterior mucosa lining of the larynx, associated with the constant movement of the larynx due to swallowing, breathing and mechanically assisted respiration, causes the formation of inflammatory reaction resulting in scar tissue thereon. Such scar tissue once formed is generally permanent, and may obstruct the airway and restrict the movement of the aryntenoid cartilages. Attempts to remove it surgically may result in its regrowth.
Either form of damage to the posterior region of the larynx effects speech as well as the ability of the larynx to protect the trachea and lungs from saliva, food and/or other secretions. Accordingly it is extremely important that contact between the endotracheal tube and the posterior region of the larynx be avoided or kept to a minimum during prolonged intubation.
Devices known heretofore, such as those shown in U.S. Pat. Nos. 4,341,210 and 4,091,816 to Elam; 4,327,720 to Bronson et al; and 4,453,545 to Inoue, have generally been concerned with sealing the trachea to prevent secretions in the pharynx from entering the lungs via the larynx and trachea. Some of these devices disclose anchoring the endotracheal tube longitudinally by inflating additional cuffs around the larynx wherein the cuffs are in contact with the larynx itself. In this respect, these prior devices fail to address or consider the axial position of the endotracheal tube relative to the critical posterior region of the larynx, or the injurious effect caused by contact between the larynx and the tube or cuffs on the function of the larynx.
The present invention overcomes these problems by providing an endotracheal airway device wherein the axial position of the tube within the larynx can be modified to reduce or avoid contact between the tube and the delicate posterior region of the larynx, and in particular the aryntenoid cartilages and the posterior commissure.